Java regex program to match parenthesis "(" or, ")".

Following regular expression accepts a string with parenthesis −

"^.*[\(\)].*$";

• ^ matches the starting of the sentence.

• .* Matches zero or more (any) characters.

• [\(\)] matching parenthesis.

• $ indicates the end of the sentence.

Example 1

 Live Demo

import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SampleTest {    public static void main( String args[] ) {       String regex = "^.*[\(\)].*$";       //Reading input from user       Scanner sc = new Scanner(System.in);       System.out.println("Enter data: ");       String input = sc.nextLine();       //Instantiating the Pattern class       Pattern pattern = Pattern.compile(regex);       //Instantiating the Matcher class       Matcher matcher = pattern.matcher(input);       //verifying whether a match occurred       if(matcher.find()) {          System.out.println("Input accepted");       }else {          System.out.println("Not accepted");       }    } }

Output 1

Enter data: sample(text) with parenthesis Input accepted

Output 2

Enter data: sample text Not accepted

Example 2

 Live Demo

import java.util.Scanner; public class Example {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter email address: ");       Scanner sc = new Scanner(System.in);       String e_mail = sc.nextLine();       //Regular expression       String regex = "^.*[\(\)].*$";       boolean result = e_mail.matches(regex);       if(result) {          System.out.println("Valid match");       } else {          System.out.println("Invalid match");       }    } }

Output 1

Enter email address: sample(text) with parenthesis Valid match

Output 2

Enter email address: sample text Invalid match